The studies outlined in this proposal will continue a project designed to investigate individual differences in pain sensitivity. The previous grant focused primarily on self report instruments as predictors of pain reactivity. As a result of this research the current proposal emphasizes a multiple response system approach to pain sensitivity. In Study I the response systems which will be investigated are; the conscious awareness of the subject, several subsystems of the autonomic nervous system, and several endocrine functions. Self report instruments which were found to be correlated with pain sensitivity in prior grant studies will be used to tap into the subject's awareness of pain reactivity. Electrophysiological measures will be employed to index autonomic functioning. Catecholamine and cortisol assays of plasma samples will be used to measure endocrine functioning. The paradigm in which these measures will be obtained is one of anticipation-stress-relaxation, the stress being the performance of the cold pressor task. Measures of these three response systems will be correlated with behavioral and self report indices of pain sensitivity in a canonical correlation analysis to judge the degree of association between the response systems and sensitivity measures. Study II will investigate central nervous system responses as reflected in brain potentials and several self report indicators of anxiety. The paradigm used in this study will be adaptation of the contigent negative variation model used to study cortical indices of orienting and expectancy. A signal will be presented which warns that shock will be delivered. During the ensuing interval the contigent negative wave will be recorded as an index of expectancy/anxiety. Then the shock will occur and early and later components of the potential evoked by this stimulation will also be recorded. Several psychometric measures of anxiety along with the self report instruments of Study I will be employed. Components of both the pre and post shock waveform together with the self report scores will be compared with pain sensitivity measures in a canonical correlation analysis.